Selectable keying apparatus



Sept. 14, 1954 J. R. MacKAY 2,68%343 SELECTABLE KEYING APPARATUS Filed Oct. l1, 1950 4 Sheets-Sheet l lffiunmwm g 700 RM 5. Maw 1 4 Sheets-Sheet 2 IN1/imola. J70/1% if fiar/fag m I k.

Sept. 14, 1954 J. R. MaCKAY SELECTABLE KEYING APPARATUS Filed Oct. ll, 1950 Sept. 14, 1954 J. R. MaoKAY 6899343 SELECTABLE KEYING APPARATUS Filed Oct. l1, 1950 l 4 SheeLS-Sheet 3 JNVENTOR. /aw QJ/kg;

Sept. 14, 1954 J. R. MaCKAY SELECTABLE KEYING APPARATUS 4 Sheets-Sheet 4 Filed Oct. l1, 1950 xl WW" w Patented Sept. 14, 1954 SELECTABLE KEYING APPARATUS John R. MacKay,

to Wallace &

Tiernan poraticn of New Jersey Packanack Lake, N. J., assigner Company, Inc., a cor- Application October 11, 1950, Serial No. 189,499

3 Claims. 1 This invention relates to keying apparatus, such as employed for keying an electrical control circuit in a signal transmitting system or the like, and more particularly relates to keying mechanisms of selectable character, viz. wherein any one of a plurality of messages may be selected and translated into keying operation of the Ysignificance or to be used under specific circumstances, and where from time to time it is desired to transmit one or another of such messages. It may be explained that for the purpose of 'the present specification and claims, the term message is used to mean any series of character elements which can be translated into a corresponding series of modications of one or more electrical circuits, each such series customarily constituting a multiplicity of the character elements having individual durations or successive spacing in time, which differ as the series progresses and which at least in part represent the distinctive character of the message.

Thus, for example, such message may consist -of a series of letters or other characters in the international Morse code (each of which is composed of character elements such as dots and dashes); the series of characters may spell out one or more Words of ordinary intelligible character, or .may consist of a combination of letters and numbers having some special signiiicance. Alternatively, apparatus of the nature hereinbelow described may be employed for the keying of messages which consist of other than Morse code characters, e. g. another series of a multiplicity -of character elements having predetermined signicance for signaling, remote controiling or like operations.

By way of example, a selectable keying mechanism of the present type is of special utility for sea, air or other vessels which are required to transmit any one of a multiplicity of predetermined messages, as by radio, light signal or the like, toY indicate the locationk of the vessel in a (Cl. S40- 357) particular area or to transmit a standardized request or statement of information to a remote observer. Quite frequently, such messages may consist simply of a combination of letters or numbers in accordance with a special signaling code. A device of the present sort is thus sometimes described as a multi-code keyer, in affording selection of a variety of pre-set code combinations of letters for transmission. To avoid confusion, however, such combinations are herein described as messages, the term code being generally restricted to the sense of the international Morse or like code, directly employed for electrical circuit control.

An important object of the present invention is to provide apparatus of the character described, involving improved and more eicient means for selectively keying an electrical circuit in accordance with any one of a plurality of predetermined messages. A' specic and particularly important object is to provide such apparatus wherein the actual electrical keying operation is performed, in an improved manner, by a single switch or equivalent device, selectively in accordance with any one of several desired messages, such improved arrangement providing a much more reliable, as Well as simplied structure, e. g. in comparison with devices requiring separate keying contactors for the selectable messages. A still further object is to provide novel and eiective apparatus wherein selection of the message to be transmitted is achieved by mechanical means, e. g. while the actual keying operation is performed by a single switch device. In these and other respects, the apparatus is preferably desgined to require only a minimum of electrical contacts that may need adjustment, replacement or other maintenance, as distinguished from equipment that involves a plurality of separate switches or contactors, for either message selection or message transmission or both.

Another object is to provide keying apparatus which by reason of the aforesaid and other characteristics is especially quiet in operation, which is of essentially compact yet rugged character and which imposes only a relatively small load on its driving motor or the like. Subsidiary objects are to aiTord such apparatus wherein a relatively small and inexpensive motor may be employed for automatic drive and wherein the Wear and tear on bearings, gears `and other moving parts is essentially minimized, especially by reason of the low level of power required for operation.

Still further objects are the provision of improved apparatus of the described character, having a durable and efficient structure, requiring little attention for service or the like, and yet involving unusual ease and convenience of operation (e. g. in selecting the message to be transmitted) and affording special advantage or facility with respect to manufacture and with respect to the original or other set-up of predetermined messages for transmission.

To these and other ends, important features of the improved apparatus, especially as embodied in presently preferred forms of the sort hereinbelow described, include the provision of a plurality of message devices, e. g. a plurality of circular message cams coaxially arranged in side-by-side relation, together with a follower device for engaging any single one of the cams, and means actuated by such device for operating a keying switch. The follower device is advantageously arranged to be shifted transversely of the cams, the switch actuating means thus embodying provision for mechanically transmitting the reciprocations of the follower to the switch, in all positions of the follower. The means for selecting a desired message to be translated, thus comprise means effecting relative transverse movement between the assembly of message devices and the follower element, specifically and preferably by displacing the follower along a linear path which is, for instance, parallel to the axis about which the cams are rotated.

The switch actuating means more particularly may involve, in such structure, a member elongated lengthwise of said path and thus continuously engageable by the follower device in all of its selected positions. Means are also preferably provided for continuously operating the message devices, e. g. motor means arranged to rotate the assembled circular cams in unison, for corresponding reciprocation of the follower (in accordance with the surface configuration of the selected cam) to operate the keying switch pursuant to the selected message. Y The apparatus also conveniently includes other structure, especially means for shifting the follower along its messageselecting path, as by a member rotatably or other- Vwise manually actuated from an operators position, including if desired, means to indicate the selected message and to retain the follower in its correspondingly selected position, all of the above as Well as other features and structures being described in more detail as embodied in the examples of the mechanism set forth below.

The accompanying drawings illustrate certain specific structures embodying the invention and designed for automatic keying of a message selected from a plurality of predetermined messages.

Referring to the drawings:

Fig. 1 is a fragmentary elevation of the face of a panel to which an embodiment of the invention, such as shown in Fig. 2, may be mounted, Fig. 1 showing certain operating and indicating means on the face of the panel;

Fig. 2 is a horizontal section on line 2 2 of Fig. 1, but showing most elements in plan, of a presently preferred embodiment;

Fig. 3 is a vertical section on line 3-3 of Fig. 2;

Fig. 4 is a vertical section on line 4 4 of Fig. 2;

Fig. 5 is a side elevation of the device of Fig. 2, viewing the latter at the right-hand side;

Fig. 6 is a transverse sectional view, largely in plan, showing another embodiment of the invention;

Fig. 7 is a section on line 1--1 of Fig. 6; and

Fig. 8 is a fragmentary view, generally similar-Y to Fig. '7 but with certain parts removed, of another embodiment of the invention.

Referring rst to Figs. 1 to 5 inclusive, the particularly advantageous mechanism there shown is designed for automatic keying of any one of a plurality of messages selected by turning an operating orrcontrol knob 20 to any one of a plurality of index positions 22 on the dial 23, each index position bearing a suitable designation to indicate, either in full or by reference, the corresponding message. While by way of example, the illustrated device affords a selection of nine messages, respectively carried on nine message cams as described below, it will be understood that the mechanism may afford selection from greater or less numbers of messages, in accordance with the requirement of service, such selectability, over a considerable range being afforded by incorporation of more or less message cams as will be apparent from the following description.

The apparatus, which may be mounted in any position, i. e. with respect to the panel 24 (which carries the dial 23') or with respect to panels other than vertical, is essentially carried by spaced forward and rear mounting plates 25, 26, conveniently described as vertical with the device positioned as shown in Fig. l. Journalled in suitable bearings 21, 28, respectively associated with the plates 25, 26, a shaft 23 lcarries a plurality of message cams 30, clamped between a collar 3| and a nut 32 on the shaft, the nut engaging a suitably threaded portion 33 of the shaft, it being understood that the cam members 30 are centrally apertured to t over the shaft. Each of the cam members consists essentially of a circular disk having a peripheral edge or surface 34 contoured to represent a specific message, for example by appropriate high and low portions designating, in a circumferential direction, successive characters and spaces of the Morse code. Although other arrangements of high, low or indeed intermediate levels may be provided in the cam contour for coaction with a suitable switching arrangement, the illustrated device, simply by way of example, involves high spots on each cam to represent dots and dashes, the intermediate depressions or low spots representing spaces between such elements and between characters thus represented. For further example, it may be assumed that the periphery of each cam carries four letters, each in the Morse code, to constitute the message, i. e. the particular signal or intelligence to be transmitted. The several cams thus may carry respectively different messages, for selection as will presently appear. While the several cams may be constructed of metal or other material, a nonmetallic substance such as a hard phenolic resin has been found particularly suitable both for quietness of operation and for long-wearing qualities. Conveniently, the sides or peripheral corners of the edge face 34 of each `cam may be bevelled as shown at 35, to afford a V-shaped or like channel extending circumferentially between successive cams, for better mechanical strength of the projections and for operational distinction between the adjacent cams, and ease of follower positioning.

The assembly of cams 30, conveniently in sideby-side abutting relation, thus provides a plurality of message devices, any one of which may be selected for control of the circuit to be keyed. Although it will now be appreciated that the set of cams may in some cases constitute an integral structure (herein, for purposes of definition,

'nevertheless described as a plurality of cams) or may involve somewhat greater spacing between the individual, disk-like cams than as shown, the

illlustrated assembly affords a convenient type of -each other, as by means of a hole 38 in each,

through-which a suitable locating pin (not shown) may be temporarily or permanently inserted, i. e. traversing allof the cam disks in the stack.

Through appropriate gears 39, 40 respectively mounted on a projecting portion of the shaft 29 and on the drive shaft 4| of an electric motor 42, the cam assembly is adapted to be driven continuously by the motor, for example to turn in the direction of the arrows, the motor being conveniently mounted on the rear plate 26.

For actuation by any selected one of the cams a follower device generally designated 44 includes a follower ringer 45 adapted to bear on the peripheral surface 34 of a cam, the structure 44 including a member 4B from which the nger 45 projects and which is pivoted, at its edges, between upstanding ears 41, 48 of a supporting v "block 49. The pivot pins 59, 5l (inthe ears 41, 48)

thus supporting the follower member 45, permit the latter to rock about the pivot axis, i. e. with reciprocation of the finger 45 as occasioned by the high and low portions of the cam periphery.

'The block 49 is slidably carried on a square bar 52 which extends between the plates 25, 2B and thus affords means for guiding the follower 44 and permitting the latter tovbe shifted along a linear path transverse of the cams and parallel to their axis. In consequence, the follower structure may be shifted along the bar 52, for engagement of the nger 45 with any selected one of the cams.

While other means may be provided for adjusting or setting the position of the follower (for example as in other figures hereinbelow described), a particularly advantageous structure comprises the cylindrical member 54 mounted on or with a shaft 55 that projects outwardly of the plate 25 and through the panel 24 to carry the knob 29. The cylindrical member 54, which is thus journalled between the end plates 25, 26 as shown and which can be directly rotated by turning the knob 29, is constructed with a helical groove 51 continuously engaged by a stud or pin 59 projecting from the block 49. Since the axis of the cylinder 54 is parallel to the bar 52 and Ythus to the path of lateral displacement of the follower 44, rotation of the cylinder 54 by the knob 20 causes the stud 59 to advance along the groove l51, e. g. in the fashion of a lead screw, so as to displace the block 49 along its guiding and supporting bar 52. As a result, the adjustment thus effected by turning the knob 2U shifts the follower finger 45 from one to another of the cams 39, the pitch of the groove 51 and the dial indications 22 being mutually designed so that the successive positions of the finger, i. e. at successive cams, will be represented by correspondingly successive positions of the pointer 69 (on the knob) at the index points 22.

For actual keying operation, the apparatus may Yinclude a switch generally designated 62, con- 'single or multiple circuit controlling operations and responsive to two or more positions of reciprocation of the follower device, the drawings illustrate, for simplicity, an enclosed switch structure of the Micro-switch type and diagrammatically indicated as including (again for simplicity) a pair of normally closed contacts 55 adapted to be opened upon depression of a switch operating member 65, the latter conveniently embodying a roller 61. Preferably, the switch 62 is of a positive, snap-action type, quickly responsive to small displacements of its operating roller 61 in opposite directions.

For actuation of the switch, the follower member 49 has a projecting arm 19, extending at a right angle thereto as shown in Fig. 3, and having at its outer end a ball-shaped abutment 12 disposed to engage the face of an elongated platen 14, the platen 14 constituting part of a plate or frame generally designated 15 and pivoted, by projecting ears 1E, 11 on a shaft 19 which extends between the plates 25, 23. The platen 14 thus extends in a direction parallel to the path of lateral shift of the follower 44 along the bar 52, and is pivoted to rock or swing about an axis, i. e. at 19, remotely spaced from the platen portion and similarly parallel to the path of the follower. As shown, the ball-shaped projection 12 on the follower arm 1G engages the inner surface of the platen 14, while the outer surface of the platen is adapted to abut the roller 61 for operation of the switch 62.

In order to hold the follower finger 45 against the surface of the selected cam, a coil spring is disposed under compression between the block 49 and the follower arm 19. The same spring effect urges the remote end of the arm 19, i. e. at the projection 12, against the platen 14, the parts being shown in Fig. 3 with the finger 45 at a low level of the cam surface 34. In the latter position, the outer surface of the platen is resting against the roller 51 and the switch member 35 is depressed inwardly, for example to open position of the contacts 55, or to other circuit controlling condition as may be desired for a low spot of the cam. When the follower finger 45 rides up on a high spot of the cam surface 39, e. g. upon rotation of the cam, the follower device is rocked about its pivots 59, 5i (counterclockwise as seen in Fig. 3) and the arm 19 is carried inwardly against the spring. Pressure of the platen on the switch roller 61 is correspondingly relieved, permitting the latter to move outwardly under the influence of its own compression spring (not shown), shifting the switch contacts to the opposite position, e. g. permitting the contacts 65 as shown to close, or otherwise establishing circuit conditions desired to correspond with a high spot of the cam surface. When the follower nger again reaches a low level of the cam, a reverse operation of the follower and the platen takes place, depressing the switch roller 51 and again reversing the circuit controlling condition of the switch.

Although the structure of the switch itself and its included spring may afford suicient means to arrest the outward or switch-depressing movement of the elongated member or platen 14, an adjustable stop 82 may be provided, if desired, to arrest the platen 'i4 positively at a safe point in its switch-depressing travel. As shown, the stop 82 may be constituted by a screw appropriately threaded in a supporting clamp 84.

For positive and more convenient setting of the follower 44 in desired position along the bar 52, means may be provided to lock such device releasably in each of its selectable positions. For example, as shown in Figs. 2, 4 and 5, the outer face of the plate' 25 carries a supplemental plate 85 provided with a circular row of depressions or openings 86 around the shaft 55 and facing out- `follower adjacent the several cams, e. g. as denoted by the dial index points 22. A pair of arms 88, 89 extending outwardly from a collar 98 secured on the shaft 55 support, at their ends, a flat spring ring 92 which is spaced slightly from the surface of the circular plate 85 and which has a pair of opposite apertures 93, 94, between the arms 88, 89. The apertures 93, 94 engages a corresponding pair of balls or like members, e. g. bearing balls 95, 98, which are similarly adapted to seat in the recesses 86, the diameter of the recesses 86 and of the openings 93, 94 being somewhat smaller than the diameter of the balls 95, 96. It Will thus be seen that as the shaft 55 is turned, the spring ring 92 carries the ball members 93, 94 around along the path constituted by the recesses 86, urging the members 95, 96 toward .the path. In consequence, as the balls reach an opposed pair of the recesses B6, the downward force of the spring ring 92 (exerted toward the plate 85 at the openings 93, 94) seats the balls in the corresponding recesses 86. Thus at each such position, the rotatable assembly is releasably locked against casual or inadvertent displacement, although the spring ring yields readily to manual rotation of the knob 28, for advance of the balls out of a pair of recesses 86 and along the surface of the plate 85, i. e. to the next pair of recesses.

The illustrated apparatus is also adapted for association with supplemental contact or switch operating devices, as for example Where a supplemental signal is to be transmitted in timed relation to the selected message or to a series of repetitions of such message.Y For instance, the mechanism of Figs. 2 to 5 may include a supplemental gear 98 carried on the shaft 29 of the cams and meshing with a gear 99 which is arranged to rotate a supplemental cam disk |80, having its contoured periphery engaged by the operating roller |8| of a suitable contact device, as of the Micro-switch type, indicated at |82. For instance, the cam disk |88 and switch |82'may be arranged to transmit a long dash or continuous signal after a predetermined number of revolutions of the cam shaft 29 and during a predetermined further number of such revolutions. The cam disk |88 by the described gearing, is thus rotated by the same motor 42 as is employed to drive the main cam assembly.

Referring again to the arrangement for shifting the follower device 44 selectively past the cams,

means may be provided, if desired, for arresting the device at the ends of such path. Thus for example, studs |84, |85 mounted as shown on the bar 52 are disposed to be engaged by the block 49 when it brings the follower nger 45 into engagement respectively with the outermost of the cams 38 in one direction or the other.

The operation of the' structure of Figs. 1 to 5 will now be essentially self-evident from the foregoing description. Assuming that the attendant desires to transmit a given signal, he first turns the knob 28 to the index position 22 representative of such signal. Through the instrumentality of the helical groove 51 on the member 54, the follower block 49 and the follower 44 itself are shifted along the bar 52, i. e. to a position of engagement of the finger 45 with that one of the cams which represents the selected message. The parts are releasably locked in this position by the device including the spring ring 92 andthe ball members 95, 96. It will be noted that throughout the entire range of shift of the follower, i. e. from one end to the other of the cam assembly, it remains in operative engagement with the remainder of the switch actuating mechanism, i. e. by engagement of the projection 12 with the platen 14, the pivotal support of the latter being such that rocking motion of the platen is the same, wherever engaged by the projection l2. Having selected the message to be sent, the operator effects energization of the signal or other transmitting circuits (not shown) and starts the motor 42. The cam shaft 29 and cam assembly thereafter rotate, turning the selected cam surface past the follower finger 45. As the cam makes each complete revolution, the follower device is reciprocated in accordance with the defined series of dots and dashes (or other character elements) and the keying switch 62 is correspondingly actuated, i. e. to key the signal or other circuit in accordance with the message.`

Continued rotation of the cam assembly effects repeated transmission of the message, e. g. once for each revolution where such is the relation of the message-defining contour of the circumference of the cam. At the end of a transmitting interval, the motor is simply arrested and the energization of the signal or other circuit interrupted. If it is desired to transmit a different message the knob 28 is simply turned to the desired index point; indeed change may be made, if necessary, without interrupting the rotation of the cams, since the side-bevelled nature of the cam surfaces permits the nger 45 to ride sidewise with ease from a low spot of one cam t0 a high spot of the adjoining cam.

It will now be apparent that the described mechanism fully achievesg the several objects mentioned above, and in fact affords a particularly convenient and easily operated keying device, useful to select any of a desired plurality of messages, for radio transmission, light signaling or other signaling or control purposes. The entire structure is remarkably rugged, yet allows an unusual simplicity of electrical parts, e. g. essentially in requiring only the single switch 62, which may itself be of a conventional type. There is no large series of electrical contacts to require adjustment or repair, either with respect to the selection of messages or with respect to the transmission of individual messages. Both the operation of selecting messages and the cam or like actua-tion for the selected messageare entirely mechanical. At the same time since there is only one cam follower, rather than a separate member and set of contacts for each cam, the load on the driven assembly is remarkably light, minimizing wear of the various moving parts and permitting the use of a relatively small and inexpensive motor 42. Selection of messages is achieved by convenient manual rotation of an exposed device such as the knob 28 guided by appropriate indicating means, the helical Vgroove arrangement on the cylinder 54 affording a positive and reliable location of the follower device 44 in any of the desired positions.

Figs. 6 and 7 show one of various other means which may alternatively be used (although with somewhat less advantage than the presently preferred structure of Fig. 2) for selective disposition of the cam follower and for switch actuation. In Figs. 6 and 7 the cams 38 will be understood to `beimounted on. a shaft 29-for rotation by a suitablel motor (not shown) in the same manner as the like elements of Fig. 2. Here the follower member I IU comprises an arm pivoted at one end to a'block I-|-I sliding on the square bar I|2, the vouter end of the follower carrying a roller ||4 which engages the contoured periphery of the cam 30. At its upper side, the roller ||4 is abuttedby. the surface of a long roller I I5 journallled between the side armsl IIS, I|'| of a frame structure generally designated I I8, which is pivoted on anaaxis at IIS, parallel to the bar ||2 and thus parallel to the axis of the cam shaft 2S. A compression spring |22 urges the frame structure I2|8 and thus the long roller I I5 downwardly against the follower roller I I4, holding the latter on the surface ofthe cam 30.

Constituting a lever about its pivot axis IIS, |20, the opposite end of the frame structure Ill carries an adjustable screw |24 or other projecting member adapted to abut the operating member |25-of a switch |21, for example a device of the Micro-switch type having contacts |28 normally open when the member I 25 is elevated and closed by depression of the member |25. In consequence as the cam 30-turns, the follower member IIIl' rocks about its pivot |30, swinging the frame structure IIB about its own pivots IIS, |20, and actuating the switch member |25.

While the position of the follower supporting block. I I I on the bar I I 2 can be adjusted by means of the sort shown in Fig. 2, e. g. a helically grooved device, the arrangement of Figs. 6 and '7 includes afrack |32 carried by the block III in parallel relation to the bar l l 2, the rack being engaged by a pinion |34 onthe shaft |35 which can be turned by a suitable knob |36 outside the panel or supporting plate |38. If desired, releasable locking means |46, similar to the structure 85--95 of Fig. 2, may be provided for the shaft |35, to hold the follower Iii) in engagement with any selected one of the cams 3U. It will be observed that asv the follower device, including the block ill, is adjusted along the bar II2 by rotation of the pinion |34, the upper face of the roller I I4 slides laterally along the surface of the roller |15, the length of the latter being such as to maintain engagement of the follower, for switch actuation in the selected position.

Fig. 8 shows another embodiment, specically another arrangement of means for shifting the follower transversely of the cams. While the follower shifting means of Fig. 8 or of Figs. 5 and 7 may be associated with other instrumentalities such as shown in Fig. 2, the arrangement of Fig. 8 is conveniently exemplined in a device otherwise of the type represented in Figs. G and '7. Here instead of the rack and pinion type, means of a lever or linkage character is employed, conveniently also in combination with gearing for more positive actuation of the linkage. Specifically, the block llia to which the follower arm IIOa is pivoted and which rides on the bar H2, carries a pair of headed pins |42, |43 respectively disposed in slots |44, |45 at the ends of arms |45, |41 that are designed to rock about corresponding axes represented by shafts or pins |45, |49. For actuation of one, and preferably both of the arms |45, I4', suitable means may comprise a central pinion 5$i on a shaft |35a, the pinion being disposed in mesh with gear segments |52, |53 respectively connected, say integrally, with the arms |45, |41. In consequence as the shaft |35a is turned by the operating knob |36 l() (Fig. 6), the Vsegments |52, |53 and with them the arms 46, |41 are rocked about their axes, it being noted, in passing, that in some cases one of the arms |46, |47 with its corresponding gear segment may be omitted, or indeed a single such arm may be directly carried on the shaft e of the knob, thus omitting the gearing in situations not requiring such wide angular movements of the knob. In all cases, including the specific embodiment of two arins |46, Uil moved in the same direction, the engagement of one or more arm-carried means such as the slots |44, |45, with one or more coacting means such as the pins |42, |43, translates the rotative motion (imparted by the knob) into displacement of the follower block Ia lengthwise of the bar i2, shifting the cam follower itla transversely of the assembly of cams S0. The roller llt is thus selectively disposed in engagement with any desired one of the cams.

As indicated above, the remaining structure of the device of Fig. 8 may be of the sort indicated in one or another of the other embodiments, for example, including an elongated member operatively related to the follower in all of its positions, such as the elongated roller l5 of Figs. 6 and 7. Thus in the device of Fig. 8 as well as in the other figures, means are provided for selectively adjusting the follower into any of a plurality of cam-engaging positions, while maintaining the operative relation of the follower to the remainder of the switch-actuating parts. it will also be noted that devices such as shown in Figs. 6 to 8 partake of many of the advantages described above relative to Figs. i to 5 inclusive, such as simplicity and ruggedness of structure, the use of only a. single electrical contacting device, and the embodiment of purely mechanical means for message selection and switch actuation from any of a plurality of message cams.

It is to be understood that the invention is not limited to the specic apparatus herein shown and described but may be embodied in other forms without departure from its spirit.

I claim:

l. Selectable keying apparatus, comprising a keying switch including a member movable to actuate the switch, a plurality of coaXially juxtaposed rnessage cams each having a circular periphery contoured to represent a message, means for rotating said cams about their common axis, a cam follower adapted to engage the periphery of a single one of said cams, a lever supporting Said follower and operatively connected to said switch actuating movable member, said lever being pivoted for movement about an axis parallel to said cam axis, spring means biasing said lever in a direction to hold said follower in engagement with said means operable to shift said lever and follower along a path parallel to the cam axis to engage the follower selectively with said cams, said shifting means comprising a iixed noncircular bar extending parallel to the cam axis, a carriage supporting a pivot for said lever and having a non-circular aperture conforming to and slidably receiving sais7 driving said carriage along said bar including manually rotatable means and means for converting rotation of said manually rotatable means into linear movement of the carriage, said noncircumr bar and aperture being effective to absorb all torques applied to the carriage by said spring means through said lever so that operation of the cams and follower does not transmit any binding force to the carriage driving means, and

bar, and means for the carriage is shiftable along said bar at all times.

2. Selectable keying apparatus comprising a keying switch including a switch actuating member, a plurality of coaxially juxtaposed message cams each having a circular periphery contoured to represent a message, means for rotating the cams about their common axis, a switch actuating lever, an elongated platen on said lever and extending parallel to said cam axis, said platen having a portion aligned with and adapted to engage said switch actuating member, said lever being pivoted for rotation about an axis parallel to said cam axis, a cam follower adapted to engage the periphery of a single one of said cams, a cam follower lever supporting said follower and having an arm extending in cooperative relationship with said platen to transmit motion thereto, means operable to shift said follower lever and follower along a path parallel to the cam axis to engage the follower selectively with said cams while moving said follower lever arm along said platen, said shifting means comprising a fixed non-circular bar extending parallel to the cam axis, a carriage supporting a pivot for said follower lever and having a noncircular aperture conforming to and slidably receiving said bar, a spring retained between said follower lever and said carriage and biasing said cam follower lever in a direction to maintain said cooperative relationship, to hold said actuating lever in engagement with said actuating member, and to hold said cam follower in engagement with one of said cams, and means for driving said carriage along said bar including manually rotatable means and means for converting rotation of said manually rotatable means into linear movement of the carriage, said noncircular bar and aperture being effective to absorb all torques applied to the carriage through said follower lever and spring so that operation of the cams and follower does not transmit any binding force to the carriage driving means, and the carriage is shiftable along said bar at all times.

Y 3. Selectable keying apparatus comprising a keying switch including a switch actuating member, a plurality of coaxially juxtaposed message cams each having a circular periphery contoured to represent a message, means for rotating the cams about their common axis, a switch actuating lever having one arm aligned with said switch actuating member, an elongated platen roller extending parallel to said cam axis on another arm of said lever, said lever being pivoted for rotation about an axis parallel to said cam axis, a cam follower roller adapted to engage the periphery of a single one of said cams and located between said follower roller and said platen roller, a cam follower lever supporting said follower roller, means operable to shift said follower lever and follower along a path parallel to the cam axis to engage the follower selectively with said cams while moving said follower lever arm along said platen, said shifting means compris-v ing a fixed non-circular bar extending parallel to the cam axis, a carriage supporting a pivot for said follower lever and having a non-circular aperture conforming to and slidably receiving said bar, a fixed spring retainer, a spring retained between said retainer and said one arm of said switch actuating lever and biasing said switch actuating lever in a direction to hold said platen roller in engagement with said cam follower roller and to hold said cam follower roller in engagement with one of said cams, and means for driving said carriage along said bar including manually rotatable means and means for converting rotation ofV said manually rotatable means into linear movement of the carriage, said non-circular bar and aperture being effective to absorb all torques applied to the carriage through said follower lever so that operation of the cams and follower does not transmit any binding force to the carriage driving means, and the carriage is shiftable along said bar at all times.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 852,743 Stakes May 7, 1907 873,270 Schmidt Dec. 10, 1907 1,135,040 Missbach Apr. 13, 1915 1,526,538 Ford Feb. 17, 1925 2,183,713 Field Dec. 19, 1939 2,463,688 Graybill et al Mar. 8, 1949 

